Delaying kindergarten entry for a year — aka “redshirting” — doesn’t help kids much in the long run, writes Michael Hansen, a Brookings researcher and father of a boy who’s turning five this summer.

An estimated 3.5 to 5.5 percent of kids eligible for kindergarten — usually boys born in the summer months — are held back each year. Affluent whites, who can afford another year of preschool, are the most likely to redshirt.

Delay Kindergarten at Your Child’s Peril, warn neuroscientists Sam Wang and Sandra Aamodt, authors of Welcome to Your Child’s Brain: How the Mind Grows From Conception to College, in the New York Times.

Nine percent of children old enough to start kindergarten are “redshirted” each year by parents who want to give them an edge, they write. But the advantages usually fade by the end of elementary school. “In high school, redshirted children are less motivated and perform less well.”

In a large-scale study at 26 Canadian elementary schools, first graders who were young for their year made considerably more progress in reading and math than kindergartners who were old for their year (but just two months younger). In another large study, the youngest fifth-graders scored a little lower than their classmates, but five points higher in verbal I.Q., on average, than fourth-graders of the same age. In other words, school makes children smarter.

High achievers benefit from skipping a grade, they add. Acceleration has twice the effect on achievement as programs for the gifted.

Children do best when they’re challenged, but not overwhelmed.

Learning is maximized not by getting all the answers right, but by making errors and correcting them quickly. In this respect, children benefit from being close to the limits of their ability. Too low an error rate becomes boring, while too high an error rate is unrewarding. A delay in school entry may therefore still be justified if children are very far behind their peers, leaving a gap too broad for school to allow effective learning.

Young children’s brains are developing rapidly. For most, the best possible contest is the classroom, Wang and Aamodt believe. That’s especially true for disadvantaged children. The trend to move back the cutoff date for starting kindergarten is hurting children from low-income families, they write.

My husband skipped a grade in elementary school. My sister skipped in middle school. Neither faced much of an error rate in the higher grade. My daughter’s half-sister skipped high school, starting college at 14. It was not an academic challenge. Now 18, she’s started graduate school in classics.